I did not get straight forward approach, so I used below SQL script to create Approved Request first and then used "SMS_UserApplicationRequest" Management Object class to Approve, Reject or RetryIntstall the request.
SQL Script to create approved request:
INSERT INTO UserApplicationRequests(UserID, MachineResourceID, ApplicationID, ModelID, CurrentState, LastChanged, LastChangedBy, Comments, Source, RequestGuid)
VALUES(@UserID, @MachineResourceID, @ApplicationID, @ModelID, @CurrentState, @LastChanged, @LastChangedBy, @Comments, @Source, @RequestGuid)
VB.Net code to Approve, Reject or RetryInstall:
Dim approveRequestClass As New ManagementClass("SMS_UserApplicationRequest")
Dim moConn As ManagementScope = GetManagementScope()
If...